Alichtenberg

Yesterday when I started my car up a warning saying Fault and Differential Lock below it came on with the 4 wheels and axel symbol showing the rear differential symbol. I restarted the car and it went away. Then when I parked it that night I heard a big creak when turning the the steering wheel to the left and thought something busted in the right front wheel chamber. I am wondering if I should get both of these checked out or wait until they happen again? Also could the creak have come from the 21" tires rubbing against the wheel well? I know they rub when I turn the steering wheel all the way to the left or right doing a U-turn and that my brothers R8 will do it too due to the size of the tires; but I have never heard it creak like that. Any suggestions and or comments? (Apparently the Cayenne does not log the faults I have had thus far, such as all wheel drive fault and the low coolant level, so when the technician looks at the log info he does not see any of the faults or information I see or tell them about).

P.S: My steering wheel feels like it keeps going to the right, should I get my alignment checked out as well?